Windward O‘ahu’s Kāne‘ohe Bay is the largest bay in the Hawaiian Islands, and the only one in the main islands with all three types of reef habitat: a barrier reef, patch reefs and a broad fringing reef system along its shoreline. The bay also contains large sand flats, a number of extensive seagrass beds and some of the only remaining functioning estuarine (the convergence of river and ocean) habitats on O‘ahu.
As a result, the bay is home to some of the highest numbers and greatest diversity of fish, marine invertebrates and native marine algae anywhere on the island. It is frequented by green sea turtles, and used by sharks for birthing grounds, manta rays for foraging habitat and spinner dolphins for resting. The bay is also home to the only functioning rock-wall fishponds remaining on O‘ahu.
Like Maunalua Bay on Oahu’s south coast, Kāne‘ohe Bay is being overharvested and degraded by invasive algae and sedimentation. The Nature Conservancy, which is already partnering with the State and the University of Hawai‘i to rid the bay of invasive algae, is now working to reduce sedimentation flowing into the bay from the He‘eia ahupua‘a, a large 2,248-acre land division extending from mauka (mountains) to makai (the sea) with an historic fishpond at its ocean end.
The He‘eia ahupua‘a was once a thriving wetland, but today it is overrun with non-native grasses, trees and weeds. A Department of Defense dumpsite, surrounding development and two major highways that extend through the watershed contribute to urban sources of land-based pollution and sediment, which flow to the sea during heavy rains and choke the bay’s reefs.
The Conservancy’s primary goal at He‘eia is to protect the coral reefs and other marine resources of Kāne‘ohe Bay. To accomplish that, it is supporting an ambitious multi-partner project to restore a traditional Hawaiian wetland system. Begun by the Ko‘olaupoko Hawaiian Civic Club, the restoration effort goes by the name Mahuahua ‘Ai o Hoi and is led by the community non-profit Kako‘o ‘Ōiwi.
The effort to transform He‘eia grew out of a 2007 strategic plan to protect the bay, which included interviews with more than 50 community members, scientists and other stakeholders. Sedimentation was identified as a major problem, and to begin to address it the community obtained from the Hawai‘i Community Development Authority a 38-year lease on 400 acres of former taro fields that had been converted to ranchland in the early 1900s.
Of the 400 leased acres, about half are wetland. The community anticipates converting up to 200 acres to taro production, and has already established a small lo‘i kalo (taro field) with walls built higher than usual to capture storm flows and act as sediment traps. To further reduce the amount of sediment flowing onto the reefs, and protect the surrounding lands from projected sea level rise, the community plans to restore native wetlands and fishponds.
The community’s broader vision is to restore a prized tradition: He‘eia as a breadbasket. In addition to cultivating taro, members plan to grow organic greens, sweet potato and other crops. In the upland areas, a forest dominated by alien tree species will be replanted with native and Polynesian introduced plants such as kava, breadfruit, pandanus and banana.
For the He‘eia community and for the Conservancy, the goal is not only to reduce the amount and rate of sedimentation flowing into the bay and smothering coral reef habitat, but also provide alternative sources of food and a suite of agricultural and aquacultural jobs for local families.
The larger hope is that the project will transfer knowledge of traditional Hawaiian land management practices and customs to a new generation and strengthen the connection between people, their ‘āina (land) and the sea.
Other project partners include the native plant organization Hui ku Maoli Ola, Paepae o He‘eia, Hawaii Community Development Authority, Hawaii Community Foundation, U.S. Army Corps of Engineers, U.S. Fish & Wildlife Service, Office of Hawaiian Affairs, State Office of Planning, the National Oceanic and Atmospheric Administration’s Pacific Services Center, and the State Department of Land and Resources Division of Aquatic Resources.March 11, 2011